Electrical connectors



June 13, 1961 R. E. LARKIN ELECTRICAL CONNECTORS 2 Sheets-Sheet 1 FiledMarch 29, 1957 June 13, 1961 R. E. LARKIN 2,988,724

ELECTRICAL CONNECTORS Filed March 29, 1957 2 Sheets-Sheet 2 UnitedStates Patent 2,988,724 ELECTRICAL CONNECTORS Robert E. Larkin,Milwaukee, Wis., assignor to Cutler- Hammer, Inc., Milwaukee, Wis., acorporation of Delaware Filed Mar. 29, 1957, Ser. No. 649,447 Claims.(Cl. 33995) This invention relates generally to electrical connectors.

More specifically the invention relates to spring or clip typeelectrical connectors adapted to be employed in electrical devices suchas, but not limited to, switches.

It is an object of the invention to provide new and improved connectingmeans whereby electrical conductors may be quickly, conveniently andsecurely connected to electrical devices without the aid of tools.

Another object is to provide such connecting means which are simple,compact, and employ a minimum number of elements all of which lendthemselves to economical mass production.

Still another object is to provide such connecting means wherebyelectrical conductors are securely locked in place but may be readilyreleased.

A further object is to provide such connecting means having portionswhich serve as an integral part of the electrical device wherein theyare employed.

A still further object is to provide connecting means which readilyengage one or more wire conductors having the same or differentdiameters.

Other objects and advantages of the invention will appear hereinafter.

The accompanying drawings illustrate certain embodiments of theinvention which will now be described, it being understood that theembodiments illustrated are susceptible of modifications with respect tocertain structural details thereof without departing from the scope ofthe appended claims.

In the drawings:

FIGURE 1 is a side elevation of a trigger switch incorporating theinvention shown within the handle of an electrical device such as aportable tool;

FIG. 2 is a bottom plan view of said switch;

FIG. 3 is a top plan view of the base portion of said switch withcertain members removed to show details;

FIG. 4 is a sectional view of said switch showing it in open position;the upper portion of the section, specifically, the trigger lever,frame, contact carrier and both insulator plates the lower portion ofthe section, specifically, the base member, which is taken substantiallyalong line 44 of FIG. 3;

FIG. 5 is a detail view of a bussing clip carried within the base ofsaid switch;

FIG. 6 is a detail view of one of two contact clips carried within thebase of said switch;

FIG. 7 is a top plan View of an alternative form of base member for usewith said switch;

FIG. 8 is a sectional view of said alternative form of base member takenalong line 8-8 of FIG. 7, and

FIG. 9 is a detail view of an alternative form of bussing clip which issimilar in certain respects to that shown in FIG. 5.

FIGS. 1 and 2 show a trigger switch 20 incorporating the inventionmechanically secured within the handle of a suitable device 21 such as aportable electric drill. Assume that device 21 employs an electric motor(not shown) from which the conductors M1 and M2 extend and that themotor (not shown) is energizable from the conductors L1 and L2 whichextend into the handle of the device and which are appropriatelyconnected to a suitable power source (not shown). Briefly, conductors M2and L2, inserted into the base of normally open switch 2a), areelectrically connected to each other through Patented June 13, 1961 icebussing means contained therein. Conductors M1 and Ll are eachelectrically connected to stationary contacts Within switch 20 and whenthe contacts are bridged upon closure of the switch the motor (notshown) of device 21 is energized.

Referring specifically to FIGS. 1, 2, 3 and 4, switch 20 comprises aone-piece base member 22 which is preferably formed by molding fromphenolic insulating material such as Bakelite or other suitableelectrical insulating material. Base 22 is provided with chambers 23 and24, best seen in FIG. 3, which accommodate the contact clips 25 and 26,respectively. Clip member 25, identical to clip 26 (see FIG. 6), ispreferably formed by stamping from sheet bronze or other suitableresilient conductive material. The flat upper end portions of the clips25 and 26 are perforated to accommodate the shanks of the brass drivescrews 27 and 28, respectively, which when forced into suitable openingsprovided within base 22, secure the clips intheir respective chambers.Each clip is in electrical contact with its drive screw and the head ofeach screw serves as one of the stationary contacts of the switch. Ifpreferred, means of securement other than drive screws may be employed,provided that such other means are suitable as contacts. The mid-portionof each clip is bowed and the lower or free end of each clip, whichterminates in a sharp working edge, is reversely curved as shown. Eachclip is suspended or floats within its respective chamber so that spaceexists between the lower portion of the clip and the floor of thechamber. Such space allows for downward travel of the lower portion ofclip incidental to force being exerted on a conductor in engagement withthe clip tending to withdraw the conductor from the chamber, as willhereinafter become apparent. Since it is not necessary, prior to theinsertion of a conductor, that portions of the clip bear against therear wall of the chamber, special shaping or bending of the clip tocritical tolerances to accomplish such positioning during assembly isavoided. It is apparent, however, that upon insertion of a conductor,the clip must bear against the rear wall of the chamber to effect properengagement of the conductor. The sharp working edge of each clip is inproximity to, but does not touch, the forward wall of the chamber.

FIGS. 2, 3 and 4 make clear that the floor of each chamber 23 and 24 isprovided with a pair of rectangular access holes 29 and 30, and 31 and'32, respectively, which open into recesses 33 and 34, respectively,formed in the lower outer surface of base 22. In practice, as is clearfrom FIGS. 1 and 4, the bare end of insulated conductor L1, which may bea solid wire or stranded wire which has been tinned to afford rigidity,is inserted through hole 32 into chamber 24 containing contact clip 26thus forcing the free end of said clip upward in a direction away fromthe floor of said chamber and forcing the working edge of said clip awayfrom the forward wall of said chamber. Simultaneously, a portion of theclip is forced against the rear wall of the chamber where it remains aslong as the conductor is contained within the chamber. Preferably,conductor L1 is pressed sufficiently far into chamber 24 so that theinsulated portion thereof extends into recess 34 thus insuring that nouninsulated portions extend from switch base 22. Conductor L1 slipsbetween the working edge of clip 26 and the forward wall of chamber 24and the tendency of said clip, now forced against the rear wall of thatchamber, to spring back to normal position effects secure mechanical andelectrical engagement of said conductor between the working edge and theforward wall. Forces exerted on conductor L1 tending to withdraw it fromchamber 24 only serve to make the connection more secure as clip 26 isforced closer to the forward wall of said chamber by its own bias and bythe downward pulling action of said conductor on the working edge ofsaid clip. To disconnect conductor L1 from clip 26, a suitableinstrument or tool (not shown) such as a stilf piece of wire or thelike, is inserted through hole 31 into chamber 24 to force said clipaway from said conductor thus freeing the latter for removal. Ifpreferred, conductor L1 may be inserted through hole 31 and hole 32 maybe reserved for the use of the removal tool (not shown).

It is to be understood that conductor M1 is connected to contact clip 25in the same manner that conductor L1 is connected to clip 26. ConductorM1 may be inserted into chamber 23 through hole 29 or 30, as desired,and the unoccupied opening reserved for the use of the removal tool (notshown). It is apparent that the connecting means hereinbefore describedreadily accommodates itself to engage wire conductors of varyingdiameters. Obviously, openings having shapes and sizes other than thatshown may be employed to allow for insertion of conductors of varioussizes. If preferred, instead of the separate holes 29 and 30, or 31 and32, a single access hole or slot (not shown) having an elongated contourand capable of accommodating one or more conductors and the removal tool(not shown) may be employed.

Base 22 is further provided with a chamber 35 adapted to accommodate abussing clip member 36, best seen in FIG. 5, which, while notelectrically connected to any portion of switch 20, serves as aconvenient means for electrically connecting conductors L2 and M2 toeach other. Bussing clip 36, preferably formed of resilient bronze isprovided with a flat, substantially rectangular, upper end portion andis bowed and reversely curved at its lower or free end in a mannersimilar to contact clips 25 and 26. In addition, the sharp working edgeof clip 36 is provided with an indentation 37 which facilitates thelocation of the removal tool (not shown) when such tool is employed.Bussing clip 36 is suspended in chamber 35 and is secured therein by aninsulating plate 38, preferably formed of molded phenolic insulatingmaterial such as Bakelite or similar material, which holds the upperportion of said clip against a shoulder or ledge 39 integrally formed inbase 22. The lower or free end of clip 36 is disposed above the floor ofchamber 35 and the reversely curved portion, after the conductors havebeen inserted, bears on a projection 40 integrally formed on the rearwall of chamber 35. Since, in the embodiment shown, clip 36 is toaccommodate at least two conductors, chamber 35 is provided with threerectangular access holes 41, 42 and 43 which open into a recess 44, thepurpose of which recess is the same as that of recesses 33 and 34,formed in the lower outer surface of base 22. Conductors L2 and M2engage and are disengageable from bussing clip 36 in the mannerexplained in connection with conductor L1 and clip 26. Preferably,conductors L2 and M2 are inserted through holes 41 and 43, respectively,or vice versa, thus reserving center hole 42 for the use of removal tool(not shown), but obviously other arrangements are possible. Thus,openings having shapes and sizes other than those shown may be employed.If preferred, instead of three openings 41, 42 and 43, a singleelongated access hole or slot (not shown) capable of accommodating amultiplicity of vari-sized conductors and a removal tool (not shown) maybe employed. Clip 36 is pivotable on projection 40 so that the workingedge of said clip is biased tightly against conductors employedtherewith even if the diameters of two conductors being employed shoulddiffer. For example, if conductor L2 is of small diameter and conductorM2 is of somewhat larger diameter, or vice versa, both are tightlyengaged by clip 36 since the clip adjusts itself by pivoting toaccommodate them.

If preferred, instead of clip 36 a bussing clip like 36a shown in FIG. 9may be employed in chamber 35. Clip 36a has a slot 37a dividing itslower end portion which allows the working edges on either side thereofto move independently to adjust themselves to the size of the particularconductor associated therewith.

If preferred, untinned stranded wire may be employed with the inventionif the so-called removal tool (not shown) is utilized to efiect thenecessary displacement of clips 25, 26 or 36, as the case may be, topermit the insertion of such wire into the respective chambers.

FIGS. 7 and 8 show a base member 77 which may be employed with switch 20instead of base 22. Base 77 may be secured within the handle in exactlythe same manner as base 22. It is apparent, however, that base 77 isprovided with a tapped opening 78 which enables switch 20, whenemploying such base, to be secured within a suitable device (not shown)in a manner other than that shown in FIG. 1. Base 77 is not providedwith bussing means and it is apparent that the chambers 79 and 80 whichare adapted to carry contact clips are disposed within base 77 in alocation other than that shown in connection with base 22.

The novel press-in lead constructions hereinbefore described enablesrapid, economical and positive attachment of conductors and permitsconvenient detachment thereof. The incorporation of bussing connectionswithin the switch eliminates the necessity of a separate externalconnection. The materials employed and their arrangement and dispositionwith respect to each other insure that no exposed portions of the switchunit can be electrically charged.

I claim:

1. As a terminal connector in an electrical device, in combination, aninsulating casing forming part of said device having a chamber formedtherein, said chamber having laterally spaced side walls and a floor, aresilient conductive member comprising an upper flat end portion seatingon a surface of said casing along the open end of said chamber, a bowedportion connecting with an end of said fiat portion at the open end ofsaid chamber and extending downwardly in said chamber in spaced convexlycurved relation to one side wall thereof, a reversely curved portionconnecting with the lower end of said bowed portion in spaced relationto the floor of said chamber, and a lower flat portion connecting withthe other end of said reversely curved portion and extending at an angleto and terminating at a free end adjacent but in spaced relation to theside wall of said chamber opposite said one side wall, means securingsaid upper fiat end portion of said member in place on said surface ofsaid casing, and at least two apertures extending through said floor ofsaid chamber exteriorly of said casing, each of said aperturesaccommodating a wire conductor disposed and gripped between the free endof said lower flat portion of said member and the last recited side wallof said chamber.

2. The combination according to claim 1 wherein said means securing saidupper flat end portion of said conductive member on said surface of saidcasing comprises a conductive rivet having a head overlying said upperflat end portion which serves as a stationary contact for saidelectrical device.

3. As a bussing connector in an electrical device, in combination, aninsulating casing forming part of said device, a chamber formed in saidcasing, said chamber having laterally spaced side walls, a fioor and anintegrally formed rib on one side wall of said chamber, a resilientconductive member comprising an upper flat end portion seating on asurface along the open end of said chamber, a bowed portion connectingwith an end of said flat portion at the open end of said chamber andextending downwardly in said chamber in convexly curved relation to saidone side wall of said chamber, a reversely curved portion connectingwith the lower end of said bowed portion and engaging with said rib inspaced relation to said floor and a lower flat portion connecting withsaid reversely curved portion and extending at an angle to andterminating at a free end adjacent but in spaced relation to the sidewall opposite said one side wall, means securing said upper flat endportion of said member in 5 6 place on said surface of said casing, andat least three References Cited in the file of this patent aperturesextending through the floor of said casing exteriorly of said casing,each of said apertures accommo- IT S TES PA NTS dating a wire conductordisposed and gripped between t e free end of said lower fiat portion ofsaid member 5 3:33: 32? and the last specified side wall of saidchamber. 2705785 B d 7 1955 4. The combination according to claim 3wherein said enan er conductive member has an indentation formed on the2,705,787 Benander 1955 free end of its lower flat portion in line withone of said 21181626 Benander P 1955 apertures to facilitate location ofthe insertion and Ie- 10 2,738,432 Benallder 13, 1956 moval 1:0 1,2,773,248 Smith Dec. 4, 1956 5. The combination according to claim 3wherein said 2,779,828 Despard Jan. 29, 1957 conductive member has aslit extending inwardly from 2,841,673 Benander July 1, 1958 the freeend of its lower flat portion to permit gripping 2,875,424 Hubbell Feb.24, 1959 wire conductors of difierent sizes on each side of said slit.15

